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author | Trond Myklebust <trond.myklebust@hammerspace.com> | 2019-01-29 21:40:10 -0500 |
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committer | Trond Myklebust <trond.myklebust@hammerspace.com> | 2019-07-06 14:54:49 -0400 |
commit | bf11fbdb20b385157b046ea7781f04d0c62554a3 (patch) | |
tree | fc24ca63f5e1529f713cc9243716dfc45075bd36 /fs/nfs/sysfs.c | |
parent | 10b7a70cbb81a62353f763c3343ac0c48410696f (diff) | |
download | linux-bf11fbdb20b385157b046ea7781f04d0c62554a3.tar.bz2 |
NFS: Add sysfs support for per-container identifier
In order to identify containers to the NFS client, we add a per-net
sysfs attribute that udev can fill with the appropriate identifier.
The identifier could be a unique hostname, but in most cases it
will probably be a persisted uuid.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'fs/nfs/sysfs.c')
-rw-r--r-- | fs/nfs/sysfs.c | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/fs/nfs/sysfs.c b/fs/nfs/sysfs.c index 7070711ff6c5..4f3390b20239 100644 --- a/fs/nfs/sysfs.c +++ b/fs/nfs/sysfs.c @@ -9,7 +9,12 @@ #include <linux/fs.h> #include <linux/slab.h> #include <linux/netdevice.h> +#include <linux/string.h> +#include <linux/nfs_fs.h> +#include <linux/rcupdate.h> +#include "nfs4_fs.h" +#include "netns.h" #include "sysfs.h" struct kobject *nfs_client_kobj; @@ -67,3 +72,116 @@ void nfs_sysfs_exit(void) kobject_put(nfs_client_kobj); kset_unregister(nfs_client_kset); } + +static ssize_t nfs_netns_identifier_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + struct nfs_netns_client *c = container_of(kobj, + struct nfs_netns_client, + kobject); + return scnprintf(buf, PAGE_SIZE, "%s\n", c->identifier); +} + +/* Strip trailing '\n' */ +static size_t nfs_string_strip(const char *c, size_t len) +{ + while (len > 0 && c[len-1] == '\n') + --len; + return len; +} + +static ssize_t nfs_netns_identifier_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + struct nfs_netns_client *c = container_of(kobj, + struct nfs_netns_client, + kobject); + const char *old; + char *p; + size_t len; + + len = nfs_string_strip(buf, min_t(size_t, count, CONTAINER_ID_MAXLEN)); + if (!len) + return 0; + p = kmemdup_nul(buf, len, GFP_KERNEL); + if (!p) + return -ENOMEM; + old = xchg(&c->identifier, p); + if (old) { + synchronize_rcu(); + kfree(old); + } + return count; +} + +static void nfs_netns_client_release(struct kobject *kobj) +{ + struct nfs_netns_client *c = container_of(kobj, + struct nfs_netns_client, + kobject); + + if (c->identifier) + kfree(c->identifier); + kfree(c); +} + +static const void *nfs_netns_client_namespace(struct kobject *kobj) +{ + return container_of(kobj, struct nfs_netns_client, kobject)->net; +} + +static struct kobj_attribute nfs_netns_client_id = __ATTR(identifier, + 0644, nfs_netns_identifier_show, nfs_netns_identifier_store); + +static struct attribute *nfs_netns_client_attrs[] = { + &nfs_netns_client_id.attr, + NULL, +}; + +static struct kobj_type nfs_netns_client_type = { + .release = nfs_netns_client_release, + .default_attrs = nfs_netns_client_attrs, + .sysfs_ops = &kobj_sysfs_ops, + .namespace = nfs_netns_client_namespace, +}; + +static struct nfs_netns_client *nfs_netns_client_alloc(struct kobject *parent, + struct net *net) +{ + struct nfs_netns_client *p; + + p = kzalloc(sizeof(*p), GFP_KERNEL); + if (p) { + p->net = net; + p->kobject.kset = nfs_client_kset; + if (kobject_init_and_add(&p->kobject, &nfs_netns_client_type, + parent, "nfs_client") == 0) + return p; + kobject_put(&p->kobject); + } + return NULL; +} + +void nfs_netns_sysfs_setup(struct nfs_net *netns, struct net *net) +{ + struct nfs_netns_client *clp; + + clp = nfs_netns_client_alloc(nfs_client_kobj, net); + if (clp) { + netns->nfs_client = clp; + kobject_uevent(&clp->kobject, KOBJ_ADD); + } +} + +void nfs_netns_sysfs_destroy(struct nfs_net *netns) +{ + struct nfs_netns_client *clp = netns->nfs_client; + + if (clp) { + kobject_uevent(&clp->kobject, KOBJ_REMOVE); + kobject_del(&clp->kobject); + kobject_put(&clp->kobject); + netns->nfs_client = NULL; + } +} |